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Acid-induced polymerization of the group 5 mite allergen from Dermatophagoides pteronyssinus
1Department of Life Science, National Yang-Ming University, 155 Li-Nong Street, Sec. 2, Taipei, Taiwan. shliaw@ym.edu.tw
Abstract:
House dust mites are the most important source of indoor allergens and cause allergic diseases. Our studies here suggest that the group 5 allergen from Dermatophagoides pteronyssinus (Der p 5) is monomeric at neutral pH, but forms filaments at low pH. Circular dichroism measurements show Der p 5 is a helical protein, and the protein sequence reveals Der p 5 contains coiled-coil helices. The acid-induced filament assembly could be explained in part by the high content of charged residues (40%) in the coiled-coil structure. Interestingly, some of the known Dermatophagoides allergens also contain a heptad repeat, which could potentially form coiled coils. Therefore, coiled-coil helices may be one of the common structural motifs of mite allergens that contribute to their allergenicity.
Insights
House dust mite allergens, like Der p 5, can change structure. Acidic conditions cause these mite allergens to form filaments, potentially explaining their allergic impact.
Area of Science:
- Immunology
- Structural Biology
- Allergology
Background:
- House dust mites are a primary source of indoor allergens.
- These allergens trigger significant allergic diseases in susceptible individuals.
Purpose of the Study:
- To investigate the structural behavior of the group 5 allergen from Dermatophagoides pteronyssinus (Der p 5).
- To explore the potential role of structural motifs in mite allergenicity.
Main Methods:
- Circular dichroism spectroscopy to determine protein structure.
- Analysis of protein sequence for structural motifs.
- pH-dependent structural transition studies.
Main Results:
- Der p 5 exists as a monomer at neutral pH but forms filaments at acidic pH.
- Circular dichroism confirmed Der p 5 as a helical protein.
- Protein sequence analysis revealed coiled-coil structures rich in charged residues, contributing to acid-induced assembly.
Conclusions:
- Coiled-coil helices may be a common structural feature among Dermatophagoides allergens.
- This structural motif could be a key factor in the allergenicity of house dust mite proteins.